You can test accessing a protected resource using an LN payment by opening this URL in your browser after having installed and correctly configured this extension:
https://lnd-testnet-1.mably.com/ln-payreq-auth.html
You can also test accessing a protected resource using an LN signature by opening this URL in your browser:
https://lnd-testnet-1.mably.com/ln-sign-auth.html
Warning: this extension requires a running Lnd Web Client server.